Composite tennis racquet frames were traditionally made with a foam core, which acted to quiet the racquet and to prevent rattles due to debris that remained inside the hollow chamber of the racquet frame after drilling.
In recent years, composite tennis racquets have increasingly been made without foam cores, in order to reduce the weight of the racquet. Racquet companies have introduced butt caps with an end plate that can be removed by the purchaser, in order to shake out excessive drilling debris. For example, Prince Sports Group markets tennis racquets having a trap door butt cap, in which a removable, octagonal shape butt cap plate fits into an octagonal seat in the butt cap base. The plate can be removed using a key and, after debris is removed, refitted into the octagonal seat. A pair of latch members, formed on the plate, snap into a rectangular cutout formed in the butt cap base to hold the plate securely in place.